Merciless: In secretly shot video, a worker swings a vicious kick into the belly of 58-year-old Anne the elephant. Animal Defenders International planted the device because of concerns about how Anne was being treated at Bobby Roberts's Super Circus

With each repeated blow, the pitchfork makes a sickening thwack as it slams into Anne the elephant's hide.

She flinches, at one point even appearing to lose her footing under the weight of a particularly savage strike.

The disturbing images come from a secretly shot video which campaigners say lays bare the cruel reality of her life as Britain's last circus elephant.

It shows Anne enduring the abuse at the hands of her so-called carers while shackled in a dingy barn during the circus's winter break.

As well as being repeatedly hit with the pitchfork by one worker employed to feed and look after her, the 58-year-old elephant also appears to be stabbed in the face with the tool's metal prongs during one attack.

A total of 48 strikes, including kicks to her body and head, were recorded as she was left chained to the spot by her legs.

Campaigners claimed shackling Anne with leg irons is particularly cruel because she suffers arthritis and her movements are already badly hampered.

The graphic attacks were recorded over three-and-a-half weeks by a surveillance camera concealed on a farm in Polebrook, Northamptonshire.

Experts working for the pressure group Animal Defenders International (ADI) planted the device because of concerns about Anne's welfare.

In goes the pitchfork: The weapon is used to beat the animal and even to stab her in the head. The graphic attacks were recorded over three-and-a-half weeks by a surveillance camera concealed on a farm in Polebrook, Northamptonshire during the circus's winter break

They have repeatedly called for circus owner Bobby Roberts to hand over Anne so she can live out her days in a wildlife sanctuary.

But Mr Roberts, whose Super Circus began its latest tour on Thursday, insists the elephant is 'part of the family' and to separate her from the circus would cause her to 'pine away and die'.

The hidden camera also caught the abuse of other animals in the barn, including a camel, miniature ponies and horses held in stables.

Ponies and horses can be seen jumping backwards as they are kicked and slapped by a worker.

On one occasion a man spits in the face of the camel as he pushes a wheelbarrow of straw in front of it.

Anne is the oldest surviving elephant in Europe and is wheeled out in a headdress to pose for photographs with audience members up to twice a day.

And still the torture goes on: Anne, who is shackled despite having arthritis, is battered with a stave in the farm building

Elephants' life expectancy is around 70 years but the arthritis has taken its toll on her ageing body.

Campaigners have claimed her back right leg locks and weight gain has put even more strain on her frame.

The Asian elephant has been travelling with the Bobby Roberts Super Circus since the 1950s when she was bought by Mr Roberts's parents for around £3,000.

At the time she was one of many performing elephants but since then most circuses have stopped using animals.

In 2005, the RSPCA and the Government refused to intervene in her case after claims that she was being kept in appalling conditions.

Her plight then was revealed by our sister paper the Mail on Sunday and angry readers sent more than 1,500 letters to Ben Bradshaw, then Labour's Animal Health and Welfare Minister.

On show: Anne with owner Bobby Roberts, who runs the Super Circus. Anne has been with the circus since she was a baby

However ministry vets reported that Anne was in good health and kept clean and the RSPCA said there was no proof that she was a victim of 'unnecessary suffering'.

The distressing footage from ADI suggests a different story.

It was released as ministers prepare to announce new policies on the treatment of wild animals in circuses.

A consultation found 95 per cent of people said it was unacceptable to use any species of wild animal in a travelling circus.

The Government has since come under pressure to ban the practice but some expect it will unveil a framework for self-regulation instead.

Jan Creamer, who leads ADI, said her organisation has been concerned for Anne's welfare for 'many years'.

She called on police to examine the material with a view to investigating the circus for offences under the Animal Welfare Act.

Ms Creamer said: 'ADI is discussing the potential for legal action with its lawyers and will be in touch with the police.

'Poor Anne has been with the circus for over 50 years since she was a baby, having been caught in the wild and torn from her family.

'Elephants are social and extremely intelligent so this has been a living hell for her. At last we have managed to expose this circus operation for the cruel farce that it is.

'Anne's tragic story symbolises the plight of circus animals and is a shocking indictment of the circus industry at a key time as the Government considers a ban on the use of wild animals in circuses.'

Last night, confronted with the evidence, Bobby Roberts said he would fire the Romanian groom paid £8,000 a year to care for Anne.

'I'm so disgusted and I can't believe this has happened under my nose,' he said.

'We trusted him and we'd check on her every hour or so, but I can't be there 24 hours a day.'

Asked whether he would consider handing over Anne, he said: 'We have talked about sending her to a sanctuary, but the only ones are in America and the journey would kill her.

'If the circumstances were right, I would part from her. But she'd pine, like I would.'

Mr Roberts's wife Moira said: 'It would break his heart to be parted from her.'